1. Field of the Invention
The present invention relates to a brushless motor for a power tool, and more particularly, to a technique that is useful to rationalize the structure of the motor of the power tool.
2. Description of the Related Art
A power tool often utilized a motor that is driven by a DC power due to its high efficiency and high output. As for a DC motor, generally, a DC motor that includes a brush and a commutator or a brushless motor that does not include a brush and a commutator is known. A brushless motor is also referred to as a DC brushless motor or a direct current brushless motor. A brushless motor typically uses a permanent magnet in the rotor and a coil in the stator. Therefore, it is not necessary to provide a brush and a commutator. Thus, the motor can be smaller and simpler in structure.
Generally, a brushless motor includes a device for cooling the brushless motor and a rotating position detecting device for detecting the rotating position of the rotor with respect to the stator. On the other hand, the brushless motor is required to have an arrangement and configuration to save space in the power tool.
It is, accordingly, an object of the present teachings to provide a technique that rationalizes the structure of the brushless motor so as to save space in the power tool.
According to the present teachings, a representative brushless motor utilized in a power tool may comprise a stator, a rotor and a cooling fan. The brushless motor is disposed within the power tool. The brushless motor is adapted to supply driving current to the stator to drive a tool bit of the power tool by rotating the rotor. The cooling fan is molded of a magnetic or conductive material so that the cooling fan also serves as a rotating position detector that detects the rotating position of the rotor with respect to the stator. Because the cooling fan may also have a function of rotating position detector of the rotor, the inner space of the power tool can be rationalized.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.